How did the Drazi find out about the Centauri
involvement? Or are they just lucky guessers? Since Londo isn't aware
of what's going on, they couldn't have found out from him, even if they
had successfully bugged his quarters at some point.

Londo was correct about Vir not being ready to be the
ambassador: Vir is thought of as weak and ineffectual by the other
races, as demonstrated by the Drazi merchant. Though Londo's comment
to Zack was probably at least partially in jest, a little confrontation
may well be necessary before people will take Vir seriously enough
to make him an effective ambassador.

G'Kar used an analogy of a light shining on a wall
to describe how people perceive God. Lennier used a similar analogy in
"Passing Through Gethsemane"
when he described the Minbari conception of the soul to Brother Edward.

Lennier cautioned Findell about joining the Anla'shok for
the wrong reasons -- but it's arguable that that's exactly what
Lennier himself has done, since one of his goals is to impress
Delenn (he said as much in
"The Very Long Night of Londo Mollari.")
That may hold the key to his eventual betrayal of the Rangers as
predicted by Morden
("Day of the Dead.")
If faced with a choice of serving Delenn directly or serving the
Anla'shok, he might well choose the former, especially if the
choice involved a significant threat to Delenn. Such an eventuality
appears to be foreshadowed here in the conversation between Delenn
and Lennier.

Findell's reasons for joining are very close to Marcus': the death
of a family member and the desire to carry on that person's work.

Garibaldi's drunkenness won't remain a secret for long
if he's as careless as he was in ordering the pizza; the staff of
Fresh Air now potentially knows about his return to the bottle.
Whether that information will make it to anyone who knows Garibaldi
personally, of course, remains to be seen. It's possible that the
Fresh Air staff doesn't consider it out of the ordinary to deliver
food to a drunk off-duty crewmember.

Eavesdropping figured in both storylines: the Drazi bug
in Londo's quarters and Captain Montoya listening in on Lennier's
communications.

Franklin's installation of G'Kar's eye suggests another possible
instance of eavesdropping. The eye has a long range, so it's
possible someone might pick up its signals from a distance. Perhaps
that's how the Drazi found out about the Centauri -- if G'Kar read
a document on the subject they might have picked up the image from
his eye.

If that's indeed happening, G'Kar may discover it and decide the eye
isn't worth the risk. That could explain why he's missing it in the
future
("War Without End part 2.")